At the present time, in the obturation of root canal systems during root canal therapy, it is usually necessary to sear off gutta percha, i.e., to apply heat to burn off unwanted filling material (excess gutta percha). This is usually accomplished by introducing a dental instrument, such as a so-called plastic instrument, into an existing flame, such as that provided by a Bunsen burner, to heat the same and then applying the heated plastic instrument to the pulp chamber of the tooth having excess gutta percha. In this manner, excessive gutta percha is burned off so that only an amount of gutta percha necessary in the root canal is present. It should be recognized that although gutta percha is a commonly used substance to fill root canals, other deformable or beat moldable material are occasionally used to fill the root canals, but gutta percha will be used hereinafter as synonymous with a filling material for the purposes of this application.
There are several problems with this conventional method. First, the burning flame of the Bunsen burner is a hazard that may ignite other flammable material. Second, the flame must be kept constantly burning during the obturation of the root canal in view of the fact that it is used intermittently during the obturation procedure and it is not cost effective to continually extnguish and relight the flame. Third, the flame is often of such magnitude that it frightens patients (who may not be used to undergoing a dental procedure in the vicinity of a burning flame). Fourth, this obturation method requires frequent transfer of the heated dental instrument between the flame and the patient's mouth. During such transfer(s), it is a continuous hazard that the instrument may inadvertently fall, burning something, more significantly and harmfully burning the mouth of the patient. Further, in view of the necessity of such transfer(s) between the flame and the patient's mouth, there is an obvious loss of heat, i.e., the instrument cools somewhat after it is removed from the flame and before it is used operatively in the patient's mouth. This loss of heat may be significant in view of the fact that the filling material, i.e., the gutta percha, will not melt if the instrument has cooled to a temperature below the melting temperature of the gutta percha
In the prior art, the general endodontic process for filling a root canal in a tooth with gutta percha is described in U.S. Pat. Nos. 4,480,996 (Crovatto), 4,525,147 (Pitz et al.), 4,681,545 (Lapcevic), 4,894,011 (Johnson) and 5,067,900 (McSpadden).